To make the pepper jam, preheat the oven to 180°C/350°F. Arrange the capsicums and tomatoes on a baking tray and sprinkle with salt.
Bake for twenty to twenty-five minutes and set aside to cool. When completely cold, peel the capsicums and tomatoes and purée them in a blender. You can also roast the capsicums and tomatoes on direct flame. Cool, remove seeds and roughly chop or puree.
Heat the oil in a non-stick pan; add the garlic and sauté for thirty seconds. Add the capsicum-tomato purée and salt and cook for two minutes. Add the vinegar and bring to a boil.
Lower heat and add the brown sugar and chilli flakes. Cook till reduced to half the quantity. Remove from heat and set aside. Dry-roast the red chillies and coriander seeds.
Cool and pound to a coarse powder with sea salt. Marinate the prawns in a mixture of this ground masala and lemon juice for fifteen minutes. Heat the oil in a pan; add the carom seeds.
When they begin to change colour, add the onion and green chillies and sauté till golden brown. Add the ginger paste and garlic paste and sauté for thirty seconds. Add the marinated prawns and stir-fry for a few minutes.
Add a little salt, kasuri methi and garam masala powder mix well. Stir in half the roasted pepper jam. And mix till all the prawns are coated well. Add one-fourth cup of water and cook till the prawns are just done. Add coriander leaves and mix.
To serve place a ring in a serving plate an spread the remaining jam at the base. Put the prawns over this and remove the ring gently. Serve immediately.